]>
git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - mm/migrate.c
2 * Memory Migration functionality - linux/mm/migration.c
4 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
6 * Page migration was first developed in the context of the memory hotplug
7 * project. The main authors of the migration code are:
9 * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
10 * Hirokazu Takahashi <taka@valinux.co.jp>
11 * Dave Hansen <haveblue@us.ibm.com>
15 #include <linux/migrate.h>
16 #include <linux/module.h>
17 #include <linux/swap.h>
18 #include <linux/swapops.h>
19 #include <linux/pagemap.h>
20 #include <linux/buffer_head.h>
21 #include <linux/mm_inline.h>
22 #include <linux/nsproxy.h>
23 #include <linux/pagevec.h>
24 #include <linux/rmap.h>
25 #include <linux/topology.h>
26 #include <linux/cpu.h>
27 #include <linux/cpuset.h>
28 #include <linux/writeback.h>
29 #include <linux/mempolicy.h>
30 #include <linux/vmalloc.h>
31 #include <linux/security.h>
32 #include <linux/memcontrol.h>
33 #include <linux/syscalls.h>
37 #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
40 * Isolate one page from the LRU lists. If successful put it onto
41 * the indicated list with elevated page count.
44 * -EBUSY: page not on LRU list
45 * 0: page removed from LRU list and added to the specified list.
47 int isolate_lru_page(struct page
*page
, struct list_head
*pagelist
)
52 struct zone
*zone
= page_zone(page
);
54 spin_lock_irq(&zone
->lru_lock
);
55 if (PageLRU(page
) && get_page_unless_zero(page
)) {
59 del_page_from_active_list(zone
, page
);
61 del_page_from_inactive_list(zone
, page
);
62 list_add_tail(&page
->lru
, pagelist
);
64 spin_unlock_irq(&zone
->lru_lock
);
70 * migrate_prep() needs to be called before we start compiling a list of pages
71 * to be migrated using isolate_lru_page().
73 int migrate_prep(void)
76 * Clear the LRU lists so pages can be isolated.
77 * Note that pages may be moved off the LRU after we have
78 * drained them. Those pages will fail to migrate like other
79 * pages that may be busy.
86 static inline void move_to_lru(struct page
*page
)
88 if (PageActive(page
)) {
90 * lru_cache_add_active checks that
91 * the PG_active bit is off.
93 ClearPageActive(page
);
94 lru_cache_add_active(page
);
102 * Add isolated pages on the list back to the LRU.
104 * returns the number of pages put back.
106 int putback_lru_pages(struct list_head
*l
)
112 list_for_each_entry_safe(page
, page2
, l
, lru
) {
113 list_del(&page
->lru
);
121 * Restore a potential migration pte to a working pte entry
123 static void remove_migration_pte(struct vm_area_struct
*vma
,
124 struct page
*old
, struct page
*new)
126 struct mm_struct
*mm
= vma
->vm_mm
;
133 unsigned long addr
= page_address_in_vma(new, vma
);
138 pgd
= pgd_offset(mm
, addr
);
139 if (!pgd_present(*pgd
))
142 pud
= pud_offset(pgd
, addr
);
143 if (!pud_present(*pud
))
146 pmd
= pmd_offset(pud
, addr
);
147 if (!pmd_present(*pmd
))
150 ptep
= pte_offset_map(pmd
, addr
);
152 if (!is_swap_pte(*ptep
)) {
157 ptl
= pte_lockptr(mm
, pmd
);
160 if (!is_swap_pte(pte
))
163 entry
= pte_to_swp_entry(pte
);
165 if (!is_migration_entry(entry
) || migration_entry_to_page(entry
) != old
)
169 * Yes, ignore the return value from a GFP_ATOMIC mem_cgroup_charge.
170 * Failure is not an option here: we're now expected to remove every
171 * migration pte, and will cause crashes otherwise. Normally this
172 * is not an issue: mem_cgroup_prepare_migration bumped up the old
173 * page_cgroup count for safety, that's now attached to the new page,
174 * so this charge should just be another incrementation of the count,
175 * to keep in balance with rmap.c's mem_cgroup_uncharging. But if
176 * there's been a force_empty, those reference counts may no longer
177 * be reliable, and this charge can actually fail: oh well, we don't
178 * make the situation any worse by proceeding as if it had succeeded.
180 mem_cgroup_charge(new, mm
, GFP_ATOMIC
);
183 pte
= pte_mkold(mk_pte(new, vma
->vm_page_prot
));
184 if (is_write_migration_entry(entry
))
185 pte
= pte_mkwrite(pte
);
186 flush_cache_page(vma
, addr
, pte_pfn(pte
));
187 set_pte_at(mm
, addr
, ptep
, pte
);
190 page_add_anon_rmap(new, vma
, addr
);
192 page_add_file_rmap(new);
194 /* No need to invalidate - it was non-present before */
195 update_mmu_cache(vma
, addr
, pte
);
198 pte_unmap_unlock(ptep
, ptl
);
202 * Note that remove_file_migration_ptes will only work on regular mappings,
203 * Nonlinear mappings do not use migration entries.
205 static void remove_file_migration_ptes(struct page
*old
, struct page
*new)
207 struct vm_area_struct
*vma
;
208 struct address_space
*mapping
= page_mapping(new);
209 struct prio_tree_iter iter
;
210 pgoff_t pgoff
= new->index
<< (PAGE_CACHE_SHIFT
- PAGE_SHIFT
);
215 spin_lock(&mapping
->i_mmap_lock
);
217 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, pgoff
, pgoff
)
218 remove_migration_pte(vma
, old
, new);
220 spin_unlock(&mapping
->i_mmap_lock
);
224 * Must hold mmap_sem lock on at least one of the vmas containing
225 * the page so that the anon_vma cannot vanish.
227 static void remove_anon_migration_ptes(struct page
*old
, struct page
*new)
229 struct anon_vma
*anon_vma
;
230 struct vm_area_struct
*vma
;
231 unsigned long mapping
;
233 mapping
= (unsigned long)new->mapping
;
235 if (!mapping
|| (mapping
& PAGE_MAPPING_ANON
) == 0)
239 * We hold the mmap_sem lock. So no need to call page_lock_anon_vma.
241 anon_vma
= (struct anon_vma
*) (mapping
- PAGE_MAPPING_ANON
);
242 spin_lock(&anon_vma
->lock
);
244 list_for_each_entry(vma
, &anon_vma
->head
, anon_vma_node
)
245 remove_migration_pte(vma
, old
, new);
247 spin_unlock(&anon_vma
->lock
);
251 * Get rid of all migration entries and replace them by
252 * references to the indicated page.
254 static void remove_migration_ptes(struct page
*old
, struct page
*new)
257 remove_anon_migration_ptes(old
, new);
259 remove_file_migration_ptes(old
, new);
263 * Something used the pte of a page under migration. We need to
264 * get to the page and wait until migration is finished.
265 * When we return from this function the fault will be retried.
267 * This function is called from do_swap_page().
269 void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
270 unsigned long address
)
277 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
279 if (!is_swap_pte(pte
))
282 entry
= pte_to_swp_entry(pte
);
283 if (!is_migration_entry(entry
))
286 page
= migration_entry_to_page(entry
);
289 * Once radix-tree replacement of page migration started, page_count
290 * *must* be zero. And, we don't want to call wait_on_page_locked()
291 * against a page without get_page().
292 * So, we use get_page_unless_zero(), here. Even failed, page fault
295 if (!get_page_unless_zero(page
))
297 pte_unmap_unlock(ptep
, ptl
);
298 wait_on_page_locked(page
);
302 pte_unmap_unlock(ptep
, ptl
);
306 * Replace the page in the mapping.
308 * The number of remaining references must be:
309 * 1 for anonymous pages without a mapping
310 * 2 for pages with a mapping
311 * 3 for pages with a mapping and PagePrivate set.
313 static int migrate_page_move_mapping(struct address_space
*mapping
,
314 struct page
*newpage
, struct page
*page
)
320 /* Anonymous page without mapping */
321 if (page_count(page
) != 1)
326 write_lock_irq(&mapping
->tree_lock
);
328 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
,
331 expected_count
= 2 + !!PagePrivate(page
);
332 if (page_count(page
) != expected_count
||
333 (struct page
*)radix_tree_deref_slot(pslot
) != page
) {
334 write_unlock_irq(&mapping
->tree_lock
);
338 if (!page_freeze_refs(page
, expected_count
)) {
339 write_unlock_irq(&mapping
->tree_lock
);
344 * Now we know that no one else is looking at the page.
346 get_page(newpage
); /* add cache reference */
348 if (PageSwapCache(page
)) {
349 SetPageSwapCache(newpage
);
350 set_page_private(newpage
, page_private(page
));
354 radix_tree_replace_slot(pslot
, newpage
);
356 page_unfreeze_refs(page
, expected_count
);
358 * Drop cache reference from old page.
359 * We know this isn't the last reference.
364 * If moved to a different zone then also account
365 * the page for that zone. Other VM counters will be
366 * taken care of when we establish references to the
367 * new page and drop references to the old page.
369 * Note that anonymous pages are accounted for
370 * via NR_FILE_PAGES and NR_ANON_PAGES if they
371 * are mapped to swap space.
373 __dec_zone_page_state(page
, NR_FILE_PAGES
);
374 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
376 write_unlock_irq(&mapping
->tree_lock
);
377 if (!PageSwapCache(newpage
)) {
378 mem_cgroup_uncharge_cache_page(page
);
385 * Copy the page to its new location
387 static void migrate_page_copy(struct page
*newpage
, struct page
*page
)
389 copy_highpage(newpage
, page
);
392 SetPageError(newpage
);
393 if (PageReferenced(page
))
394 SetPageReferenced(newpage
);
395 if (PageUptodate(page
))
396 SetPageUptodate(newpage
);
397 if (PageActive(page
))
398 SetPageActive(newpage
);
399 if (PageChecked(page
))
400 SetPageChecked(newpage
);
401 if (PageMappedToDisk(page
))
402 SetPageMappedToDisk(newpage
);
404 if (PageDirty(page
)) {
405 clear_page_dirty_for_io(page
);
407 * Want to mark the page and the radix tree as dirty, and
408 * redo the accounting that clear_page_dirty_for_io undid,
409 * but we can't use set_page_dirty because that function
410 * is actually a signal that all of the page has become dirty.
411 * Wheras only part of our page may be dirty.
413 __set_page_dirty_nobuffers(newpage
);
417 ClearPageSwapCache(page
);
419 ClearPageActive(page
);
420 ClearPagePrivate(page
);
421 set_page_private(page
, 0);
422 page
->mapping
= NULL
;
425 * If any waiters have accumulated on the new page then
428 if (PageWriteback(newpage
))
429 end_page_writeback(newpage
);
432 /************************************************************
433 * Migration functions
434 ***********************************************************/
436 /* Always fail migration. Used for mappings that are not movable */
437 int fail_migrate_page(struct address_space
*mapping
,
438 struct page
*newpage
, struct page
*page
)
442 EXPORT_SYMBOL(fail_migrate_page
);
445 * Common logic to directly migrate a single page suitable for
446 * pages that do not use PagePrivate.
448 * Pages are locked upon entry and exit.
450 int migrate_page(struct address_space
*mapping
,
451 struct page
*newpage
, struct page
*page
)
455 BUG_ON(PageWriteback(page
)); /* Writeback must be complete */
457 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
462 migrate_page_copy(newpage
, page
);
465 EXPORT_SYMBOL(migrate_page
);
469 * Migration function for pages with buffers. This function can only be used
470 * if the underlying filesystem guarantees that no other references to "page"
473 int buffer_migrate_page(struct address_space
*mapping
,
474 struct page
*newpage
, struct page
*page
)
476 struct buffer_head
*bh
, *head
;
479 if (!page_has_buffers(page
))
480 return migrate_page(mapping
, newpage
, page
);
482 head
= page_buffers(page
);
484 rc
= migrate_page_move_mapping(mapping
, newpage
, page
);
493 bh
= bh
->b_this_page
;
495 } while (bh
!= head
);
497 ClearPagePrivate(page
);
498 set_page_private(newpage
, page_private(page
));
499 set_page_private(page
, 0);
505 set_bh_page(bh
, newpage
, bh_offset(bh
));
506 bh
= bh
->b_this_page
;
508 } while (bh
!= head
);
510 SetPagePrivate(newpage
);
512 migrate_page_copy(newpage
, page
);
518 bh
= bh
->b_this_page
;
520 } while (bh
!= head
);
524 EXPORT_SYMBOL(buffer_migrate_page
);
528 * Writeback a page to clean the dirty state
530 static int writeout(struct address_space
*mapping
, struct page
*page
)
532 struct writeback_control wbc
= {
533 .sync_mode
= WB_SYNC_NONE
,
536 .range_end
= LLONG_MAX
,
542 if (!mapping
->a_ops
->writepage
)
543 /* No write method for the address space */
546 if (!clear_page_dirty_for_io(page
))
547 /* Someone else already triggered a write */
551 * A dirty page may imply that the underlying filesystem has
552 * the page on some queue. So the page must be clean for
553 * migration. Writeout may mean we loose the lock and the
554 * page state is no longer what we checked for earlier.
555 * At this point we know that the migration attempt cannot
558 remove_migration_ptes(page
, page
);
560 rc
= mapping
->a_ops
->writepage(page
, &wbc
);
562 /* I/O Error writing */
565 if (rc
!= AOP_WRITEPAGE_ACTIVATE
)
566 /* unlocked. Relock */
573 * Default handling if a filesystem does not provide a migration function.
575 static int fallback_migrate_page(struct address_space
*mapping
,
576 struct page
*newpage
, struct page
*page
)
579 return writeout(mapping
, page
);
582 * Buffers may be managed in a filesystem specific way.
583 * We must have no buffers or drop them.
585 if (PagePrivate(page
) &&
586 !try_to_release_page(page
, GFP_KERNEL
))
589 return migrate_page(mapping
, newpage
, page
);
593 * Move a page to a newly allocated page
594 * The page is locked and all ptes have been successfully removed.
596 * The new page will have replaced the old page if this function
599 static int move_to_new_page(struct page
*newpage
, struct page
*page
)
601 struct address_space
*mapping
;
605 * Block others from accessing the page when we get around to
606 * establishing additional references. We are the only one
607 * holding a reference to the new page at this point.
609 if (TestSetPageLocked(newpage
))
612 /* Prepare mapping for the new page.*/
613 newpage
->index
= page
->index
;
614 newpage
->mapping
= page
->mapping
;
616 mapping
= page_mapping(page
);
618 rc
= migrate_page(mapping
, newpage
, page
);
619 else if (mapping
->a_ops
->migratepage
)
621 * Most pages have a mapping and most filesystems
622 * should provide a migration function. Anonymous
623 * pages are part of swap space which also has its
624 * own migration function. This is the most common
625 * path for page migration.
627 rc
= mapping
->a_ops
->migratepage(mapping
,
630 rc
= fallback_migrate_page(mapping
, newpage
, page
);
633 remove_migration_ptes(page
, newpage
);
635 newpage
->mapping
= NULL
;
637 unlock_page(newpage
);
643 * Obtain the lock on page, remove all ptes and migrate the page
644 * to the newly allocated page in newpage.
646 static int unmap_and_move(new_page_t get_new_page
, unsigned long private,
647 struct page
*page
, int force
)
651 struct page
*newpage
= get_new_page(page
, private, &result
);
658 if (page_count(page
) == 1)
659 /* page was freed from under us. So we are done. */
662 charge
= mem_cgroup_prepare_migration(page
, newpage
);
663 if (charge
== -ENOMEM
) {
667 /* prepare cgroup just returns 0 or -ENOMEM */
671 if (TestSetPageLocked(page
)) {
677 if (PageWriteback(page
)) {
680 wait_on_page_writeback(page
);
683 * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
684 * we cannot notice that anon_vma is freed while we migrates a page.
685 * This rcu_read_lock() delays freeing anon_vma pointer until the end
686 * of migration. File cache pages are no problem because of page_lock()
687 * File Caches may use write_page() or lock_page() in migration, then,
688 * just care Anon page here.
690 if (PageAnon(page
)) {
696 * Corner case handling:
697 * 1. When a new swap-cache page is read into, it is added to the LRU
698 * and treated as swapcache but it has no rmap yet.
699 * Calling try_to_unmap() against a page->mapping==NULL page will
700 * trigger a BUG. So handle it here.
701 * 2. An orphaned page (see truncate_complete_page) might have
702 * fs-private metadata. The page can be picked up due to memory
703 * offlining. Everywhere else except page reclaim, the page is
704 * invisible to the vm, so the page can not be migrated. So try to
705 * free the metadata, so the page can be freed.
707 if (!page
->mapping
) {
708 if (!PageAnon(page
) && PagePrivate(page
)) {
710 * Go direct to try_to_free_buffers() here because
711 * a) that's what try_to_release_page() would do anyway
712 * b) we may be under rcu_read_lock() here, so we can't
713 * use GFP_KERNEL which is what try_to_release_page()
714 * needs to be effective.
716 try_to_free_buffers(page
);
721 /* Establish migration ptes or remove ptes */
722 try_to_unmap(page
, 1);
724 if (!page_mapped(page
))
725 rc
= move_to_new_page(newpage
, page
);
728 remove_migration_ptes(page
, page
);
739 * A page that has been migrated has all references
740 * removed and will be freed. A page that has not been
741 * migrated will have kepts its references and be
744 list_del(&page
->lru
);
750 mem_cgroup_end_migration(newpage
);
752 * Move the new page to the LRU. If migration was not successful
753 * then this will free the page.
755 move_to_lru(newpage
);
760 *result
= page_to_nid(newpage
);
768 * The function takes one list of pages to migrate and a function
769 * that determines from the page to be migrated and the private data
770 * the target of the move and allocates the page.
772 * The function returns after 10 attempts or if no pages
773 * are movable anymore because to has become empty
774 * or no retryable pages exist anymore. All pages will be
775 * returned to the LRU or freed.
777 * Return: Number of pages not migrated or error code.
779 int migrate_pages(struct list_head
*from
,
780 new_page_t get_new_page
, unsigned long private)
787 int swapwrite
= current
->flags
& PF_SWAPWRITE
;
791 current
->flags
|= PF_SWAPWRITE
;
793 for(pass
= 0; pass
< 10 && retry
; pass
++) {
796 list_for_each_entry_safe(page
, page2
, from
, lru
) {
799 rc
= unmap_and_move(get_new_page
, private,
811 /* Permanent failure */
820 current
->flags
&= ~PF_SWAPWRITE
;
822 putback_lru_pages(from
);
827 return nr_failed
+ retry
;
832 * Move a list of individual pages
834 struct page_to_node
{
841 static struct page
*new_page_node(struct page
*p
, unsigned long private,
844 struct page_to_node
*pm
= (struct page_to_node
*)private;
846 while (pm
->node
!= MAX_NUMNODES
&& pm
->page
!= p
)
849 if (pm
->node
== MAX_NUMNODES
)
852 *result
= &pm
->status
;
854 return alloc_pages_node(pm
->node
,
855 GFP_HIGHUSER_MOVABLE
| GFP_THISNODE
, 0);
859 * Move a set of pages as indicated in the pm array. The addr
860 * field must be set to the virtual address of the page to be moved
861 * and the node number must contain a valid target node.
863 static int do_move_pages(struct mm_struct
*mm
, struct page_to_node
*pm
,
867 struct page_to_node
*pp
;
870 down_read(&mm
->mmap_sem
);
873 * Build a list of pages to migrate
876 for (pp
= pm
; pp
->node
!= MAX_NUMNODES
; pp
++) {
877 struct vm_area_struct
*vma
;
881 * A valid page pointer that will not match any of the
882 * pages that will be moved.
884 pp
->page
= ZERO_PAGE(0);
887 vma
= find_vma(mm
, pp
->addr
);
888 if (!vma
|| !vma_migratable(vma
))
891 page
= follow_page(vma
, pp
->addr
, FOLL_GET
);
901 if (PageReserved(page
)) /* Check for zero page */
905 err
= page_to_nid(page
);
909 * Node already in the right place
914 if (page_mapcount(page
) > 1 &&
918 err
= isolate_lru_page(page
, &pagelist
);
921 * Either remove the duplicate refcount from
922 * isolate_lru_page() or drop the page ref if it was
930 if (!list_empty(&pagelist
))
931 err
= migrate_pages(&pagelist
, new_page_node
,
936 up_read(&mm
->mmap_sem
);
941 * Determine the nodes of a list of pages. The addr in the pm array
942 * must have been set to the virtual address of which we want to determine
945 static int do_pages_stat(struct mm_struct
*mm
, struct page_to_node
*pm
)
947 down_read(&mm
->mmap_sem
);
949 for ( ; pm
->node
!= MAX_NUMNODES
; pm
++) {
950 struct vm_area_struct
*vma
;
955 vma
= find_vma(mm
, pm
->addr
);
959 page
= follow_page(vma
, pm
->addr
, 0);
966 /* Use PageReserved to check for zero page */
967 if (!page
|| PageReserved(page
))
970 err
= page_to_nid(page
);
975 up_read(&mm
->mmap_sem
);
980 * Move a list of pages in the address space of the currently executing
983 asmlinkage
long sys_move_pages(pid_t pid
, unsigned long nr_pages
,
984 const void __user
* __user
*pages
,
985 const int __user
*nodes
,
986 int __user
*status
, int flags
)
990 struct task_struct
*task
;
991 nodemask_t task_nodes
;
992 struct mm_struct
*mm
;
993 struct page_to_node
*pm
= NULL
;
996 if (flags
& ~(MPOL_MF_MOVE
|MPOL_MF_MOVE_ALL
))
999 if ((flags
& MPOL_MF_MOVE_ALL
) && !capable(CAP_SYS_NICE
))
1002 /* Find the mm_struct */
1003 read_lock(&tasklist_lock
);
1004 task
= pid
? find_task_by_vpid(pid
) : current
;
1006 read_unlock(&tasklist_lock
);
1009 mm
= get_task_mm(task
);
1010 read_unlock(&tasklist_lock
);
1016 * Check if this process has the right to modify the specified
1017 * process. The right exists if the process has administrative
1018 * capabilities, superuser privileges or the same
1019 * userid as the target process.
1021 if ((current
->euid
!= task
->suid
) && (current
->euid
!= task
->uid
) &&
1022 (current
->uid
!= task
->suid
) && (current
->uid
!= task
->uid
) &&
1023 !capable(CAP_SYS_NICE
)) {
1028 err
= security_task_movememory(task
);
1033 task_nodes
= cpuset_mems_allowed(task
);
1035 /* Limit nr_pages so that the multiplication may not overflow */
1036 if (nr_pages
>= ULONG_MAX
/ sizeof(struct page_to_node
) - 1) {
1041 pm
= vmalloc((nr_pages
+ 1) * sizeof(struct page_to_node
));
1048 * Get parameters from user space and initialize the pm
1049 * array. Return various errors if the user did something wrong.
1051 for (i
= 0; i
< nr_pages
; i
++) {
1052 const void __user
*p
;
1055 if (get_user(p
, pages
+ i
))
1058 pm
[i
].addr
= (unsigned long)p
;
1062 if (get_user(node
, nodes
+ i
))
1066 if (!node_state(node
, N_HIGH_MEMORY
))
1070 if (!node_isset(node
, task_nodes
))
1075 pm
[i
].node
= 0; /* anything to not match MAX_NUMNODES */
1078 pm
[nr_pages
].node
= MAX_NUMNODES
;
1081 err
= do_move_pages(mm
, pm
, flags
& MPOL_MF_MOVE_ALL
);
1083 err
= do_pages_stat(mm
, pm
);
1086 /* Return status information */
1087 for (i
= 0; i
< nr_pages
; i
++)
1088 if (put_user(pm
[i
].status
, status
+ i
))
1099 * Call migration functions in the vma_ops that may prepare
1100 * memory in a vm for migration. migration functions may perform
1101 * the migration for vmas that do not have an underlying page struct.
1103 int migrate_vmas(struct mm_struct
*mm
, const nodemask_t
*to
,
1104 const nodemask_t
*from
, unsigned long flags
)
1106 struct vm_area_struct
*vma
;
1109 for(vma
= mm
->mmap
; vma
->vm_next
&& !err
; vma
= vma
->vm_next
) {
1110 if (vma
->vm_ops
&& vma
->vm_ops
->migrate
) {
1111 err
= vma
->vm_ops
->migrate(vma
, to
, from
, flags
);